Magnum Cam Selection Suggestions

I have been talking with Comp Cams about this and they are recommending a cam with .513 lift. The guy says you can't go higher than .520 on the stock magnum bottom end without piston to valve clearence issues. Anyone else run into this? I thought LXguy was running .544 lift on a stock magnum bottom end?

Any help is appreciated.
Pretty freakin funny,gross valve lift has nothing to do with VP clearance. Your best choice would be to call Tim @ Bullet cams. I'm guessing the Comp guy was talking guide to retainer clearance, who knows,just do not rely on a Comp phone answer guy to give good advice,he's only looking at some limited notes.LOL